Note: The following controls are for the Famicom, but they apply equally to every version.
- or : Holding left or right makes Ninjakun run to the left or the right.
- : Press B to throw a throwing star in whichever direction Ninjakun is currently facing.
- : Press A alone to drop down from the level Ninjakun is currently standing on (except on the lowest level.)
- + or +: Tap A with a direction to make a small hop that keeps him on his current level. Hold the A button down with a direction in order to jump up to the next level in that direction. Note that it is impossible for Ninjakun to jump straight up.
This is Ninja-kun, the sole member of the force against Demon Castle. He alone must defeat all of the enemies that stand in his way with his shurikens (throwing stars) in order to progress through his mission. Contact with his enemies is not deadly, but contact with their weapons is. Ninja-kun can stun his enemies by dropping down on their head (when they're standing on the ground), or by jumping in to them from below. Every defeated enemy will leave a scroll behind. Ninja-kun can collect those scrolls for bonus points. If he is lucky, he can also capture the magic orbs that drop out of the sky. If he can collect three of them, he will be rewarded with a bonus stage.
The first enemy that Ninjakun will face are these black clad ninjas. They wield a similar weapon to Ninjakun's throwing star, and can fling a couple at him in rapid succession. Ninjakun's throwing star can cancel out Kurosu's enemy, but he must throw them just as fast or one may strike Ninjakun. A relatively weak enemy, Kurosus are easily dispatched.
These bouncing dolls attack Ninjakun with a sickle shaped weapon with a short range that does not necessarily fly straight. By altering the angle at which these fire, the Doruma can be a threat to Ninjakun even if they are not on the same level as him. Approach with caution and attempt to land behind them in order to avoid their weapon as you eliminate them.
Kabuki warriors appear after the Doruma. Their weapon of choice is bombs. They toss bombs on Ninjakun from above, which makes them generally less of threat when they are below Ninjakun. But they are still a threat when they are on the same level as they can toss the bombs quite far. Once you throw a star at a Kabuki warrior, stay underneath the path of the bombs that they lob.
The Thundsters (true name: kaminari kosou or thunder youngster) are the first enemies that are a challenge to fight face to face. They fire a very fast lightning bolt that is quite difficult to evade. Try to drop down or jump up and land on their head in order to stun them before firing a star at them to eliminate them.
The Liondance (true name: Shishimai) is the most difficult enemy to face in the whole game. Liondances are generally slow, and their attack isn't particularly fast either. However, when their weapon comes to rest, it erupts in a fire that can never be extinguished. And it doesn't take long for a lot of these fires to overwhelm Ninjakun and prevent any plans for escape. It is especially important, when dealing with Liondances, to secure two floors that Ninjakun can move between freely. Once a floor is overrun with fire, it will be difficult to use that floor for safety. The fires will eventually dissipate, but it takes a very long time. This enemy is not found in the Famicom version.
Compared to Liondances, Skeletons are relatively easy. They behave a lot like Thundsters, and are capable of throwing fast swords in rapid fire. Don't stay on the same level as Skeletons for long, since they can easily overwhelm you with their weapons. Stay on the move, and fire at Skeletons while you jump or fall to keep from getting hit. This enemy is not found in the Famicom version.
Orochis are fast lizards that spit gobs of energy, similar to the Liondances', that travel in a wave pattern, but do not erupt into fire. Once these gobs hit the side of the screen, they bounce back and keep on going. They will expire eventually, and you can destroy them with your star. They only become a problem when a number of them exist on the screen at one time. Get Ninjakun out of the area and on to a safer level of the stage before continuing to eliminate the reptiles. This enemy is not found in the Famicom version.
Armors (true name: Yoroi) are the toughest enemies to defeat. Their thick armor is impenetrable. The only way to expose their weakness is to land on their head and stun them, or jump into them from below. The later of the two methods is easier since it sets you up to kill stunned Armors quickly. Be sure to dispatch them immediately after stunning them, or they will get back up and regain their invulnerability. Patience is the key to defeating a stage full of Armors. Concentrate on one at a time and time your falls so that you land on their heads consistently. Armors are capable of firing many fast arrows from their bows in rapid succession.
The Onibi, or demon flame, only appears if you remain on one level of the stage for too long a period of time. Once it appears, it drifts back and forth on the screen, homing in on your level. It will never go away, and it can never be defeated. Therefore, in order to avoid having to deal with this nuisance, keep moving. Even if you are strategically waiting in a particular position for an enemy to fall, make sure that you jump up or fall down every once in a while to reset the time that it takes for the Onibi to appear. Once it shows up, all you can do is avoid it.
When an enemy is defeated, and the space they occupied is cleared, they leave a scroll behind. Ninjakun can collect these scrolls for a bonus. In addition, any scrolls in Ninjakun's possession at the end of the stage award even more bonus points. This is made more difficult by the presence of the fool card.
One of the eight scrolls that Ninjakun can collect in a stage contains the Princess card. Collecting the lady card automatically doubles the number of scrolls in Ninjakun's possession. It is not possible to identify which scroll has the Princess card until you pick it up. With the Princess card, the most number of scrolls that you can exit a stage with is 12.
One of the eight scrolls that Ninjakun can collect in a stage contains the Monk card. Collecting the Monk card reduces the number of scrolls in Ninjakun's possession to zero. It is not possible to identify which scroll has the Monk card until you pick it up. Once you have a number of scrolls collected (at least 5) and you have not uncovered the Monk card, avoid collecting any more scrolls if you want to earn a good bonus at the end of the stage.
One glowing magic orb will fall out of the sky in every stage. Ninjakun can attempt to collect it before it passes through the floor of the stage. Once Ninjakun collects three magic orbs, he will be presented with a bonus stage where he must attempt to collect as many magic orbs as possible in a time limit. If the magic orb lands on an enemy's head, the enemy collects the orb, and Ninjakun must defeat the enemy to release the orb again for collection.